Dental drills and similar handpieces often include an air powered turbine head containing a turbine rotor which must be lubricated each day. At present, such daily lubrication requires that the supply hose, which provides pressurized air and water, and in some instances, a source of light, to the dental drill, be uncoupled from the drill so that an elongated, flexible nozzle of a lubricant spray container can be inserted into the air inlet opening of the dental drill that leads to the turbine rotor; the lubricant, typically oil, is then sprayed into the turbine area of the drill. Following lubrication, the supply hose must be reattached to the drill. Reattachment of the supply hose to the dental drill is delicate, taxing, and time-consuming; therefore, personnel assigned the task of lubricating such dental drills often neglect it, and expensive turbines burn out faster than expected
Those skilled in the art have attempted to solve the problem of easily and effectively lubricating dental drills but have not been entirely successful. U.S. Pat. No. 3,879,851 to Landgraf discloses a device for lubricating dental drills with aerosol spray containers without disassembly of the drills prior to lubrication. The patent to Landgraf discloses an intermediate piece coupled between the turbine head and a hand grip. The intermediate piece includes a port normally sealed by a ball valve whenever the drill is operated. The nozzle of a lubricant container may be introduced into the port when the drill is not in use. However, the nozzle may not be advanced to any significant degree into the drill itself; therefore, the lubricant is not efficiently directed toward the turbine head and can dissipate inside the intermediate piece before reaching the turbine head.
U.S. Pat. No. 3,946,490 to Sotman et al. discloses a device for aerosol lubrication of dental drills. The Sotman device is a specially designed dental handpiece which includes a lubrication opening ordinarily sealed by a sliding clip or collar. A lubrication opening projects angularly into the turbine housing. During lubrication, a tube extending from the discharge port of an aerosol lubricant can is inserted through the lubrication opening; therefore, lubricant can be injected directly from the lubricant can into the turbine housing. However, the Sotman device requires substantial modification to conventional dental drill handpieces which lack such opening.
U.S. Pat. No. 4,218,216 to Sugai et al. discloses a lubrication device inserted between the end of a dental handpiece and the flexible service hose for permitting lubricant to be added to the air supply line. Rather than permitting periodic application of a lubricant from an aerosol spray container, the device disclosed by Sugai et al. continuously adds a mist oil to the compressed air channel. However, such constant lubrication poses a significantly greater risk of inadvertently injecting such lubricant into a patient's mouth as compared with the practice of periodically lubricating a dental handpiece once each day.
In addition, French Patent No. 2526-125 discloses an air motor for a dental handpiece including an air inlet and a separate lubricant branch within the motor body connected to the air inlet passage. The lubricant branch houses a spring loaded, normally closed ball non-return valve. Oil is injected into the lubricant branch, forcing open the ball non-return valve by the pressure of the lubricating device. However, the air motor disclosed within this French patent would require substantial modification of dental handpieces that are already heavily in use.
Accordingly, it is an object of the present invention to provide a dental drill lubricating device for periodically lubricating dental drills without requiring disassembly of the dental drill from the associated supply hose.
It is another object of the present invention to provide such a dental drill lubricating device which can be used without modification of the dental handpiece itself.
It is still another object of the present invention to provide a dental drill lubricating device which permits the tip of the lubricant nozzle to be inserted into an air passage within the dental handpiece itself.
Other objects, advantages and features of the present invention will become more apparent from the following specification when taken in conjunction with the accompanying drawings.